Problem: Add. $9 + 3.2 =$
Solution: There are many ways to solve this problem. Let's see two ways we can solve it. Place value table Let's line up the numbers by their decimal places. Ones $.$ Tenths ${9}$ $.$ ${0}$ $3$ $.$ ${2}$ Because $3$ is a whole number, we can add a decimal point and a $0$ behind to make the columns align. Now, let's add each place value column. Tens Ones $.$ Tenths ${9}$ $.$ ${0}$ $+$ ${3}$ $.$ ${2}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $1$ $2$ $.$ $2$ Decomposing the numbers We can group the whole numbers together and the decimals together. $\begin{aligned} &(9 + 3) + {0.2}\\\\ &=12 + {0.2}\\\\ &=12.2 \end{aligned}$ $9 + 3.2=12.2$